1. prove that 5+4cos(x)+3sin(x)=cos^2(x/2)*(3+tan(x/2))^2
2. prove that 3+2sin(x)-cos(x)=(2(2t^2+2t+1))/(1+t^2), where t=tan(x/2)
thanks :)
Problem about proving trigo+in
2015-02-04 4:51 am
回答 (2)
2015-02-04 5:39 am
✔ 最佳答案
Please Read：圖片參考：https://s.yimg.com/rk/HA07344914/o/1896089527.png
2015-02-04 00:30:10 補充：
打錯 -.-
Properties
第2行
sin 2x = 2 sin x cos x
2015-02-04 00:30:25 補充：
thx =)
2015-02-04 6:33 am
pls check:
(sin 2x) = 2 (sin x) (cos x)
(sin 2x) = 2 (sin x) (cos x)
收錄日期: 2021-04-20 15:30:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150203000051KK00089